Wet Ceiling

[Dan Schachner]

I recently purchased a '91 that was in good shape. One of the first days I had it was a rainy day and I jumped in to drive it to a mechanic for a look over. I noticed that when I accelerated water ran down the rear window, on the inside. I was concerned by this, but figured it was the humidity and cold temps. However, the problem was recurring. I pulled the headliner out, and the ceiling was wet and has some light surface rust. I plan to lightly sand the ceiling and apply POR15 to keep it as clear of issues as possible. Also, I am going to put a foam sound deadener on the ceiling to give some insulation to prevent condensation.

 

The carpet was wet when I pulled it out and I am curious if that wet carpet was contributing to the moisture. I have looked on the forum and have not seen a problem that matches mine. Anyone have thoughts on why this condensation was occurring?

[gogmorgo]

You can get moisture absorbing pouches at the hardware store if you think excessive humidity is the problem. They’re sold for controlling odours and stuff in closets or safes, toss one under each seat. Some of them are single use, but some are “rechargeable” by baking them in the oven to boil off the water.
 

But I would say it’s very likely your back window is leaking. You can confirm by using a garden hose or wand wash and watch for leakage. It’s not unusual for the urethane holding it in to fail. If that’s the case it should be pretty easy for a glass shop to cut it out and glue it back in, so long as there isn’t any rust in the frame. You might even be able to push gently from the inside and watch to see if the glass lifts off. I pulled one at a junk yard a couple years ago and barely even needed to cut the urethane, it just peelled off. 
A lot of places will just try to gob some more urethane on the inside to seal it, but that’s not a legit solution on a window that’s been installed 20+ years imo. If the urethane failed in one spot it’s failing in others. 
 

There’s also tons of other spots that can leak into the interior. A bad one I had was the a/c drain tube was plugged, and it would dump water out of the heater vents. There’s a hose on the firewall above the starter. You can pop it off pretty easily, and if water dumps out then you can shove a screwdriver or something down the hose to unblock it. The end is supposed to be pinched off to prevent dust from getting in (it’s only so effective) so don’t snip it. 

[Pete M]

time to pull the rear window and reglue.   they are notorious for separation.  be prepared to address any rust on the mating surface.

[A-man930]

On 12/27/2024 at 10:04 AM, Dan Schachner said:

I plan to lightly sand the ceiling and apply POR15 to keep it as clear of issues as possible. Also, I am going to put a foam sound deadener on the ceiling to give some insulation to prevent condensation.

I would suggest you take a good look at people's long-term experiences with POR15 before you use the product... 

[Dan Schachner]

Any tips on where to look? Everything I have read seem that it holds up really well if it is out of the sun and properly prepped and given 2 coats.

[A-man930]

6 minutes ago, Dan Schachner said:

Any tips on where to look? Everything I have read seem that it holds up really well if it is out of the sun and properly prepped and given 2 coats.

 

This has been my experience.  

I'm fully aware that I may have made some kind of critical error in prep, but I couldn't tell you what it might have been. 

Bottom line: it's brittle, and the roof skin might be the most temperature-swing sheet metal on the truck.  

 

 

[Dan Schachner]

Nice build! You mention using 2 part epoxy, what kind of product did you go with?

[A-man930]

I've used the SprayMax cans for areas too small to justify mixing up a batch.  I used left-over PPG ShopLine on my rockers and I'll be using SPI for the rest of the body. 

 

I am no body guy, but I've done a fair amount of reading and I'm in touch with some people in the know. Let your own research be your guide.